This is the resubmission of an application for a renewal of a Midcareer Investigator Award in Patient-Oriented Research (K24) in response to PA-08-151 focused in the areas of Child Psychiatry/Pediatric Psychopharmacology and the Addictive Disorders. The objectives of the applicant are to a) increase the candidate's knowledge in stimulant misuse and substance use disorders (SUD) in adolescents and young adults, b) further his involvement in training and mentoring in Child Psychiatry/Psychology and Addictions, and c) complete a five-year prospective study of the etiologies of stimulant misuse in college students. This Award would also provide the opportunity to expand a well-integrated Center for the diagnosis and treatment of adolescent SUD in Child Psychiatry at the Massachusetts General Hospital (MGH). Despite the well-documented safety of stimulants in the treatment of ADHD, it has largely been survey studies that have shown the extent of misuse (defined here as any use outside of medical indication) of stimulants in college-aged students. These studies indicate a clinical and public health concern and through this proposal the candidate would like to address and evaluate the etiological factors, context, and characteristics of misuse of stimulants in college students. Potential subjects will be screened using a brief Internet survey and those eligible will be asked to complete a direct interview. The data collected can elucidate important issues like do inherent vulnerabilities exist and manifest under certain contexts? This investigation will provide an excellent foundation for the applicant to further his knowledge. From multiple collaborative efforts, the candidate will develop specific skills related to the study of addictions and young adults with stimulant misuse and to continue his work on methodological and conceptual issues in the phenomenology and treatment of adolescents with SUD. Through didactic seminars, supervision, meetings, and involvement in the ongoing research, the applicant proposes to continue mentoring individuals at all levels. In this manner, the candidate will continue to satisfy career development and mentoring objectives of the K24 award while addressing the vexing issues of etiologies of stimulant misuse in college students. PUBLIC HEALTH RELEVANCE: By identifying and thoroughly examining this subject area, we will be better suited to dissect underlying characteristics and potential mechanisms related to the misuse of stimulants. Data derived from this proposed study will have important and directly applicable clinical and public health relevance.